The present invention relates to a document requesting system that requests a document providing system to transfer a document, and more particularly to a document requesting system that receives not only the requested document but also related documents in advance from a document providing system.
In recent years, the WWW (World Wide Web) has been widely known as a system that causes servers to provide various types of electronic information to clients through a network. The system, as shown in FIG. 1, comprises a WWW server 11 and a WWW client 12, for example. The server 11 provides document information to the client 12 via communication sections 21, 22 according to a predetermined file transfer protocol HTTP (HyperText Transfer Protocol) between the server 11 and the client 12. The spread of the WWW enables access to document information all over the world through the network.
In the system, the transfer of document files from a server to a client is basically carried out one by one. Specifically, when the user requires the display of a document, the WWW client communicates with the WWW server, which transfers the document to the WWW client, which then displays the document on the screen. To display another document, the same operation is performed again. Thus, WWW is based on the assumption that it is used only on-line.
Accordingly, to acquire information through WWW using a portable data terminal, such as a notebook computer or a PDA (Personal Digital Assistance), the portable data terminal must be connected to the network until the use of WWW is finished. Since such a portable data terminal is not always used under the conditions where it can be constantly connected to the network, it is needed to automatically download as much information as possible all at once into the portable data terminal during the connection to the network so that the contents of the information can be read even after the disconnection from the network.
One method of realizing this is a method of causing the server to transfer not only the document the user has requested to be transferred but also related documents to the client.
This approach enables the user to cause the server to transfer a plurality of documents to the client by one instruction without directing the transfer of each document. The transferred documents are stored in the client's storage medium. Specifically, the approach is based on a method of starting a program that transfers a plurality of documents according to a transfer request made by the user and storing them in the client's storage medium or a method of concatenating a plurality of documents into a single document in advance and storing the concatenated document in the client's storage medium. The approach, however, has the following problem.
When a document is requested, documents determined to be related documents must be determined beforehand on the server side. This requires the process of preparing a document list indicating related documents on the server side and sending the list to the client.
Consequently, a judgment as to which documents are related documents is entirely up to the document provider and therefore related documents cannot be specified on the client side.